Directional sound processing in a cochlear implant

ABSTRACT

A cochlear implant implementing a directional sound processing system is provided. Specifically, the cochlear implants implementing the present invention comprise a plurality of audio sensors arranged in at least one external component of the cochlear implant to spatially receive ambient sound. At least one audio sensor is located in one of the external components of the cochlear implant, while one other audio sensor is located elsewhere, such as in a component other than the first component. The cochlear implant includes an directional sound processor comprising an array processor and a sound processor to convert the received sounds into a cochlea stimulation instruction signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 11/482,709 filed Jul. 10, 2006, now U.S. Pat. No.8,285,383 issued Oct. 9, 2012, which claims benefit of co-pending U.S.Provisional Patent Application No. 60/697,730 filed Jul. 8, 2005, whichis hereby incorporated by reference herein.

BACKGROUND

1. Field of the Invention

The present invention relates generally to sound processing, and moreparticularly, to directional sound processing in a cochlear implant.

2. Related Art

Hearing loss, which may be due to many different causes, is generally oftwo types, conductive and sensorineural. Conductive hearing loss occurswhen the normal mechanical pathways which provide sound to hair cells inthe cochlea are impeded, for example, by damage to the ossicles.Conductive hearing loss is often addressed with conventional auditoryprostheses, commonly referred to as hearing aids, which amplify sound sothat acoustic information may reach the cochlea.

Profound deafness, however, is caused by sensorineural hearing loss.This type of hearing loss is due to the absence or destruction of thehair cells in the cochlea which transduce acoustic signals into nerveimpulses. Those suffering from sensorineural hearing loss are thusunable to derive suitable benefit from conventional hearing aids due tothe damage to, or absence of, the mechanism that naturally generatesnerve impulses from sound. As a result, prosthetic hearing implants suchas cochlear prostheses (commonly referred to as cochlear prostheticdevices, cochlear implants, cochlear devices, and the like; simply“cochlear implants” herein) have been developed to provide persons withsensorineural hearing loss with the ability to perceive sound.

Cochlear implants typically comprise one or more external componentsworn by the patient (also referred to as recipient, user, wearer and thelike; “recipient” herein) and internal components that are implanted inthe recipient. The external and internal components cooperate with eachother to provide sound sensations to the recipient.

The external component(s) traditionally comprise several integrated orphysically separate elements generally including one or more acousticaltransducers that sense ambient sounds, a sound processor that selectsand converts certain detected sounds, particularly speech, into codedsignals, a power source such as a battery, and an external transmitterantenna.

The internal components traditionally comprise several integrated orphysically separate elements generally including a receiver antenna, astimulator unit and a carrier member on which an electrode assembly isdisposed for stimulating the recipient's auditory nerve. The codedsignals generated by the sound processor are transmittedtranscutaneously from the external transmitter antenna to the implantedreceiver antenna, commonly located within a recess of the temporal boneof the recipient. In addition to coded sound signals, this communicationlink is often used to transmit power to the implanted stimulator unit.Conventionally, this communication link has been in the form of a radiofrequency (RF) link, although other communication and power links havebeen proposed and implemented with varying degrees of success.

The stimulator unit processes the coded signal and generates anelectrical stimulation signal to the intra-cochlea electrode array. Theelectrode array typically has a plurality of electrodes that applyelectrical stimulation to the auditory nerve to produce a hearingsensation corresponding to the original detected sound. Because thecochlea is partitioned into regions each responsive to stimulationsignals in a particular frequency range; i.e., tonotopically mapped,each electrode of the implantable electrode array delivers a stimulationcurrent to a particular region of the cochlea. In the conversion ofsound to electrical stimulation, frequencies are allocated tostimulation channels that provide stimulation current to electrodespositioned in the cochlea at or immediately adjacent to the region ofthe cochlear that would naturally be stimulated in normal hearing. Thisenables cochlear implants to bypass the hair cells in the cochlea todirectly deliver electrical stimulation to auditory nerve fibers,thereby allowing the brain to perceive hearing sensations resemblingnatural hearing sensations.

SUMMARY

In one aspect of the present invention, a cochlear implant system isdisclosed. The cochlear implant system comprises: a behind the ear (BTE)sound processing unit; a cable; a transmit unit connected to said BTE bysaid cable and configured to transmit signals from said BTE to aninternal component of said cochlear implant; a plurality ofspatially-arranged audio sensors, configured to receive ambient sound,and comprising any combination of: a sensor located in said BTE, asensor located in said transmit unit, and a sensor located in saidcable; and a directional sound processor having an array-processingstage configured to generate a directional sound signal from soundreceived by a first one of said plurality of sensors, and wherein saiddirectional sound processor is configured to combine said directionalsound signal and a signal representative of sound received by a secondone of said plurality of sensors to generate a processed sound signalfrom which sound received from non-desired directions is attenuated.

In another aspect of the present invention, a cochlear implant system isdisclosed. The cochlear implant system comprises a behind the ear BTEsound processing unit; a cable; a transmit unit connected to said BTE bysaid cable and configured to transmit signals from said BTE to aninternal component of said cochlear implant wherein each of the BTE, thecable and the transmit unit are comprised in a single cochlear implant.

In another aspect of the present invention, a cochlear implant system isdisclosed. The cochlear implant system comprises a behind the ear BTEsound processing unit; a cable; a transmit unit connected to said BTE bysaid cable and configured to transmit signals from said BTE to aninternal component of said cochlear implant wherein the cochlear implantsystem comprises a single cochlear implant.

In another aspect of the present invention, a cochlear implant having aplurality of physically separate external components is disclosed. Thecochlear implant comprises: a plurality of audio sensorsspatially-arranged on the external components to receive ambient sound,each audio sensor comprising at least one acoustical transducer, whereinat least one of the plurality of audio sensors is disposed in a first ofthe external components and a second of the plurality of audio sensorsis disposed in a second of the external components.

In another aspect of the present invention, a cochlear implant isdisclosed. The cochlear implant comprises: a plurality ofspatially-arranged audio sensors each comprising one or more acousticaltransducers; and a directional sound processor configured to processsound received by the audio sensors from a desired direction, and toattenuate sound received from other directions.

In a further aspect of the present invention, a method for deliveringstimulation signals to a recipient's cochlea representing sound receivedfrom a desired direction. The method comprises: receiving ambient soundsat a plurality of audio sensors spatially-arranged on a plurality ofexternal components of a cochlear implant; and processing sound receivedby at least some of the plurality of audio sensors from a desireddirection and attenuating sound received from directions other than saiddesired direction.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are described below in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a perspective view of an exemplary cochlear implant in whichembodiments of the present invention may be advantageously implemented;

FIG. 2 is a schematic block diagram of selected components of a cochlearimplant, in accordance with embodiments of the present invention;

FIG. 3 is a simplified perspective view of the external components of acochlear implant, in accordance with one embodiment of the presentinvention;

FIG. 4 is a simplified perspective view of the external components of acochlear implant, in accordance with another embodiment of the presentinvention;

FIG. 5 is a simplified perspective view of the external components of acochlear implant, in accordance with a further embodiment of the presentinvention;

FIG. 6 is a simplified perspective view of the external components of acochlear implant, in accordance with a still further embodiment of thepresent invention;

FIG. 7 is a simplified perspective view of the external components of acochlear implant applicable to bilateral recipients, in accordance withan additional embodiment of the present invention;

FIG. 8 is a simplified perspective view of the external components of acochlear implant applicable to bilateral recipients, in accordance witha still further embodiment of the present invention; and

FIG. 9 is a beam pattern generated by the array-processing algorithms inaccordance with the embodiment of the invention illustrated in FIG. 3.

DETAILED DESCRIPTION

Aspects of the present invention are generally directed to a cochlearimplant implementing a directional sound processing system. Adirectionally-sensitive cochlear implant of the present inventioncomprises a plurality of audio sensors spatially-arranged to receiveambient sound. At least one audio sensor is disposed in one of theexternal components of the cochlear implant, while at least one otheraudio sensor is located elsewhere, such as in an external componentother than the first component. Each audio sensor comprises at least oneacoustical transducer such as a microphone.

Such cochlear implants also include a directional sound processor thatprocesses sound received from a desired direction (“desired sounds”) andeliminates or attenuates sound received from other directions(“undesired sounds”). Embodiments of the directional sound processorcomprise an array processor composed of one or more array-processingstages. Each array-processing stage generates a directional sound signalby adaptively enhancing the sensitivity of one or more associatedsensors to the desired sounds, essentially treating undesired sound asnoise. The desired direction is determined based on, for example, theamplitudes of the incident ambient sounds or other conditions orsettings. By increasing the signal-to-noise ratio (SNR), the directionalsound signal is an enhanced representation of the ambient sound incidenton the plurality of sensors from the desired direction. The directionalsound signal is converted to a stimulation instruction signal by a soundprocessor.

The present invention will be described principally in the context ofcochlear implants. However, it will be appreciated by those skilled inthe art that the same principles are readily implemented in otherapplications.

FIG. 1 is a perspective view of an exemplary cochlear implant 120 inwhich embodiments of the present invention may be advantageouslyimplemented. In fully functional human hearing anatomy, outer ear 101comprises an auricle 105 and an ear canal 106. A sound wave or acousticpressure 107 is collected by auricle 105 and channeled into and throughear canal 106. Disposed across the distal end of ear canal 106 is atympanic membrane 104 which vibrates in response to acoustic wave 107.This vibration is coupled to oval window or fenestra ovalis 110 throughthree bones of middle ear 102, collectively referred to as the ossicles111 and comprising the malleus 112, the incus 113 and the stapes 114.Bones 112, 113 and 114 of middle ear 102 serve to filter and amplifyacoustic wave 107, causing oval window 110 to articulate, or vibrate.Such vibration sets up waves of fluid motion within cochlea 115. Suchfluid motion, in turn, activates tiny hair cells (not shown) that linethe inside of cochlea 115. Activation of the hair cells causesappropriate nerve impulses to be transferred through the spiral ganglioncells and auditory nerve 116 to the brain (not shown), where they areperceived as sound. In deaf persons, there is an absence or destructionof the hair cells. A cochlear implant 120 is utilized to directlystimulate the ganglion cells to provide a hearing sensation to therecipient.

FIG. 1 also shows how a cochlear implant 120 is positioned in relationto outer ear 101, middle ear 102 and inner ear 103. Cochlear implant 120comprises external component assembly 122 which is directly orindirectly attached to the body of the recipient, and an internalcomponent assembly 124 which is temporarily or permanently implanted inthe recipient. External assembly 122 comprises several componentsincluding a plurality of audio sensors spatially arranged on externalcomponents 122 of cochlear implant 120 for detecting sound. The spatialarrangement of the plurality of audio sensors is described in greaterdetail below.

Sound processor 126 is a directional sound processor configured togenerate coded stimulation control signals representing sound detectedby the plurality of audio sensors from a desired direction. These codedsignals are then provided to an external transmitter unit 128. In theembodiment shown in FIG. 1, sound processor 126 is a behind the ear(BTE) sound processing unit. The BTE is constructed and arranged so thatit can fit behind the outer ear 101 of a recipient. BTE may include apower source to power all elements of the cochlear implant, such as theexternal coil. In certain embodiments, the power source may bephysically disconnected from the BTE, thereby causing the BTE todiscontinue operation. Furthermore, in other embodiments, accessoriesmay be connected to the BTE to add additional functionality.

It would be appreciated by one of ordinary skill in the art that soundprocessor 126 may also comprise a body-worn sound processor, a modularsound processor or a sound processor headset. Details of the soundprocessing performed in sound processor 126 in accordance withembodiments of the present invention are discussed below.

External transmitter unit 128 comprises an external coil 130 and,preferably, a magnet (not shown) secured directly or indirectly inexternal coil 130. External transmitter unit 128 is configured totransmit the coded signals from sound processor 126, along with powerfrom a power source 129 such as a battery to internal components 124through tissue 152.

Internal components 124 comprise an internal receiver unit 132 having aninternal coil (not shown) that receives and transmits power and codedsignals received from external assembly 122 to a stimulator unit 134 toapply the coded signal to cochlear 115 via an implanted electrodeassembly 140. Electrode assembly 140 enters cochlea 115 at cochleostomyregion 142 and has one or more electrodes 150 positioned to besubstantially aligned with portions of tonotopically-mapped cochlea 115.Signals generated by stimulator unit 134 are typically applied by anarray 144 of electrodes 150 to cochlea 115, thereby stimulating auditorynerve 116.

FIG. 2 is a schematic block diagram of cochlear implant 120 illustratedin FIG. 1 in accordance with one embodiment of the present invention.Cochlear implant 120 comprises internal components 124 and externalcomponents 122 as described above with reference to FIG. 1. In theexemplary implementation shown in FIG. 2, only a portion of externalcomponents 122 is shown. In this embodiment, the portion of externalcomponents 122 shown comprises audio sensors 250 and an directionalsound processor or system 284.

As noted, the audio sensors 250 are spatially-arranged in a plurality ofexternal components of cochlear implant 120 to receive ambient sound. Asused in this context, the term “spatially-arranged” refers to adistributed arrangement of audio sensors to receive sound from aplurality of directions. This is described in greater detail below.

In some embodiments, at least one audio sensor is located in one of theexternal components of the cochlear implant such as BTE or, while atleast one other audio sensor is located elsewhere, such as in anexternal component other than the first external component. In certainembodiments, audio sensors 250 are further configured to deliver thesound sensed by the plurality of audio sensors to directional soundprocessor 284 as one or more received audio sound signals 290. Inadditional embodiments discussed below, sound received by a sensor istransmitted to directional sound processor 284 as a sensor-specificdirectional sound signal. Received audio sound signals 290 may betransferred to directional sound processor 284 via a cable or via awireless means. Audio sensors 250 and directional sound processor 284are described in greater detail below.

In accordance with aspects of the present invention, directional soundprocessor 284 comprises an array processor 280 composed of one or morearray-processing stages (described below) and a sound processor 282.Each array-processing stage executes an array-processing algorithm tomanipulate the ambient sounds provided by one or more audio sensors 250to generate a directional sound signal 292. The application of thearray-processing algorithm to received audio sound signals 290 resultsin a directional sound signal 292 in which sound components from adesired direction have an increased signal-to-noise ratio (SNR) whilesound components from other directions are being attenuated. Inembodiments of the present invention, array-processing implemented byarray-processor 280 may include the initial delaying and summing ofsensor inputs, as well as any adaptive filtering or other signalprocessing techniques associated with processing array signals. Detailsof the array-processing implemented in the present invention aredescribed below with reference to FIG. 9.

Directional sound processor 284 is configured to process sound receivedfrom a desired direction and eliminates, cancels, filters, removes, orotherwise attenuates sound received from other directions. As notedabove, directional sound processor 284 comprises an array processorcomposed of one or more array-processing stages, wherein eacharray-processing stage generates a directional sound signal byadaptively enhancing the sensitivity of the system to sounds fromdesired directions (“desired sounds”), essentially treating sound fromother undesired directions as noise. Sound processor 282 converts thedirectional sound signal to a stimulation instruction signal. Thesecoded stimulation instruction signals are then delivered to internalcomponents 124 through tissue 152. Sound processor 282 may employee asound processing scheme traditionally implemented in cochlear implantsto convert a single sound to a stimulation instruction signal. Forexample, sound processor 282 may implement the processing schemes asdescribed in U.S. Pat. Nos. 5,597,380 or 6,480,820, which are herebyincorporated by reference herein.

Specific embodiments of external component(s) 122 implementing differentconfigurations of audio sensors 250 will now be described with referenceto FIGS. 3-8. FIG. 3 is a schematic diagram of external components 122illustrated in FIG. 1 and introduced above, in accordance with oneembodiment of the present invention. In this exemplary embodiment,external components 122 are referred to herein as external components322, while audio sensors 250 are referred to as audio sensors 350.External components 322 comprise BTE 326 connected to an external coil330 via cable 332. BTE 326 is a sound processor worn behind the ear thatcontains all the physical elements required to process sound andgenerate an appropriate signal to send to external coil 330. BTE 326includes an embodiment of directional sound processor 284, referred toherein as directional sound processor 384.

In this embodiment, audio sensors 350 comprise two audio sensorsspatially-arranged to receive ambient sound. One sensor, referred to asBTE audio sensor 344, is disposed in BTE 326. The second sensor islocated in external coil 330, and is referred to as coil audio sensor342. In this illustrative embodiment, coil audio sensor 342 is locatedat the approximate center of external coil 130. It would be appreciatedby one of ordinary skill in the art, however, that the location of BTEsensor 344 and coil sensor 342 are not restricted to the positions shownin FIG. 3.

As noted, each audio sensor may comprise one or more acousticaltransducers. In this embodiment, BTE audio sensor 344 comprises a singleacoustical transducer 346, shown as a microphone in FIG. 3. Similarly,in this embodiment, coil audio sensor 342 comprises a single acousticaltransducer 348, also shown as a microphone. Either or both acousticaltransducers 346 and 348 may possess a directional or omni-directionalpolar response.

Audio sensors 342 and 344 receive ambient sound incident on theirrespective acoustical transducers 346 and 348, respectively. In theembodiment shown, each microphone 346 and 348 transmits its receivedsound to directional sound processor 384 in BTE 326. Directional soundprocessor 384 converts the received sounds to a coded stimulationinstruction signal as introduced above and described in further detailbelow with reference to FIG. 9.

As noted above, external coil 330 receives processed sounds from BTE 326and transmits these sounds to internal components 124.

It would be appreciated by one of ordinary skill in the art that soundprocessor 326 is not limited to a BTE sound processor configuration. Inother embodiments, sound processor 326 is a modular processor. A modularsound processor contains a number of physical modules, which wheninterconnected together perform the complete processing required forimplementing a cochlear implant.

FIG. 4 is a schematic diagram of another embodiment of externalcomponents 122 introduced above with reference to FIG. 1, referred toherein as external components 422. In the embodiment shown in FIG. 4,external components 422 comprise an embodiment of BTE sound processor126, referred to herein as BTE 426 and an embodiment of external coil130, referred to herein as external coil 430. BTE sound processor 426 isconnected to external coil 430 via coil cable 432.

In this embodiment of the present invention, external components 422comprise audio sensors 450 spatially-arranged across BTE 426 andexternal coil 430 to receive ambient sounds. Audio sensors 450 residingon BTE 426 are collectively referred to as BTE audio sensor 444 whilethe acoustical transducers residing on external coil 430 arecollectively referred to as coil audio sensor 442.

In this embodiment, BTE audio sensor 444 comprises four acousticaltransducers 446A-446D. The quantity of acoustical transducers 446 in BTEsensor 444 may depend on various factors including the particularmechanical design of BTE 426, the particular type of technology used torealize acoustical transducers 446, the desired characteristics of audiosensor 444, and other factors.

Coil audio sensor 442 comprises five acoustical transducers 448A-448E.Here too, the quantity of acoustical transducers 448 may depend onvarious factors including the particular mechanical design of externalcoil 430, the particular type of technology used to realize acousticaltransducers 448, the desired characteristics of audio sensor 442, andother factors.

One or more acoustical transducers 446 and 448 may possess a directionalor omni-directional polar response. In certain embodiments, microphone448E is disposed at the center of external coil 430 and has anomni-directional polar response. Furthermore, in certain embodiments,audio sensor 450 may be composed of identical acoustical transducers orcombinations of different types of acoustical transducers.

BTE 426 implements an embodiment of directional sound processor 284,referred to herein as directional sound processor 484, to process soundsreceived by audio sensors 450. Audio sensors 444 and 442 arespatially-arranged to receive ambient sound with their respectivemicrophones 446 and 448. In certain embodiments, each microphone 446 and448 transmits its received sound to directional sound processor 484disposed in BTE 426. Directional sound processor 484 converts theplurality of received sounds into a coded stimulation instruction signalas described below with reference to FIG. 9.

In alternative embodiments, directional sound processor 484 isconfigured to treat all acoustical transducers located in a particularsensor as a single transducer. In such an embodiment, the particularsensor, or the component on which the sensor is located, or directionalsound processor 484 may further comprise an array-processing stage. Asdescribed below with reference to FIG. 9, an array-processing stagemathematically combines the audio signals generated by acousticaltransducer(s) residing in the particular audio sensor to generate adirectional sound signal for that sensor. Such a directional soundsignal for a particular audio sensor is referred to herein as asensor-specific directional sound signal. Such a sensor-specificdirectional sound signal is then transmitted to directional soundprocessor 484 for additional processing as described below withreference to FIG. 9.

For example, in the embodiment illustrated in FIG. 4, coil audio sensor442 may further comprise an array-processing stage 440. Array-processingstage 440 functions as described below to convert the plurality ofsounds received by acoustical transducers 448A-448E into asensor-specific directional sound signal. Coil audio sensor 442 thentransmits this sensor-specific directional sound signal to directionalsound processor 484. Directional sound processor 484 usessensor-specific directional sound signal from coil audio sensor 442 andone or more received sounds from BTE audio sensor 444 to generate astimulation instruction signal corresponding to the sound incident onsensors 450 from a desired direction, as described below with referenceto FIG. 9.

In other embodiments, directional sound processor 484 comprises anarray-processor having a plurality of array-processing stages. In thisembodiment, a plurality of received sounds from a single audio sensor isconverted to a sensor-specific directional sound signal by one of thearray-processing stages. Another array-processing stage then utilizesthis sensor-specific directional sound signal, as well as the receivedsounds from the remaining audio sensors to generate a directional soundsignal corresponding to the sounds from all audio sensors. It would beappreciated by one of ordinary skill in the art that any number ofarray-processing stages may be implemented in alternative embodiments ofthe present invention.

It would be appreciated by one of ordinary skill in the art that theplurality of received sounds from BTE audio sensor 444 may also betreated as a sensor-specific directional sound signal in substantiallythe same manners as described above. It would also be appreciated thatboth coil audio sensor 442 and BTE audio sensor 444 may each be treatedas single sensor by directional sound processor 484. In such anembodiment, directional sound processor 484 is configured to process thesensor-specific directional sound signals from audio sensors 444 and 442to generate the directional sound signal therefrom.

It should also be appreciated that various combinations of acousticaltransducers may be used for either BTE audio sensor 444 and/or coilaudio sensor 442, and the configuration shown in FIG. 4 is merelyillustrative. For example, it is within the scope of the invention thateither sensor could comprise a single acoustical transducer while theother audio sensor comprises any number and type of acousticaltransducers.

As noted above with reference to FIG. 3, BTE processor 426 is notlimited to a BTE configuration as shown in FIG. 4. In alternativeembodiments, for example, sound processor 426 may be a modular or a bodyworn sound processor.

FIG. 5 is a schematic diagram of another embodiment of externalcomponents 122 introduced above with reference to FIG. 1, referred toherein as external components 522. In the embodiment shown in FIG. 5,external components 522 comprise an embodiment of BTE sound processor126, referred to herein as BTE 526 and an embodiment of external coil130, referred to herein as external coil 530. BTE sound processor 526 isconnected to external coil 530 via coil cable 532.

In this embodiment of the present invention, external components 522comprise audio sensors 550 spatially-arranged across BTE 526, externalcoil 530 and cable 532 to receive ambient sounds. Audio sensors 550residing on BTE 526 are collectively referred to as BTE audio sensor 544while the acoustical transducers residing on external coil 530 arecollectively referred to as coil audio sensor 542, and the acousticaltransducers residing on cable 532 are collectively referred to as cableaudio sensor 554.

BTE audio sensor 544 comprises one and preferably more acousticaltransducers 546. The number of microphones in BTE sensor 544 may dependon various factors including the particular mechanical design of BTE526, the particular type of technology used to realize acousticaltransducers 546, and the desired characteristics of audio sensor 544.

Similarly, coil audio sensor 542 comprises one and preferably moreacoustical transducers 548. Again, the number of acoustical transducersin coil audio sensor 542 may depend on various factors including but notlimited to those noted above.

Cable audio sensor 554 comprises five acoustical transducers 556A-556Edisposed along coil cable 532. Acoustical transducers 556 may be locatedat any position along cable 532. In one embodiment, acousticaltransducers 556 have equidistant interstitial spacing while in otherembodiments the interstitial spacing between neighboring acousticaltransducers 556 varies. As with the other audio sensors, the quantity ofacoustical transducers in coil cable sensor 554 may depend on variousfactors including but not limited to those noted above.

It should also be appreciated that one or more acoustical transducers546, 548 and 556 may possess a directional or omni-directional polarresponse. In the illustrated embodiment, audio sensors 544, 542 and 554are spatially-arranged to receive ambient sounds with their respectiveacoustical transducers 546, 548 and 556. In certain embodiments, eachacoustical transducer 546, 548 and 556 transmits its received sounds todirectional sound processor 584 in BTE 526. Directional sound processor584 converts a plurality of received sounds into a stimulationinstruction signal as described below with reference to FIG. 9.

In alternative embodiments, directional sound processor 584 may treatthe acoustical transducers located in a particular sensor as a singlesensor, as described above with reference to FIG. 4. As noted, in suchan embodiment, the particular sensor, or the component on which thesensor is located, may further comprise an array-processing stage asdescribed elsewhere herein. This additional array-processing stage mayfunction substantially similar to the array-processing stages discussedbelow with reference to FIG. 9.

In the embodiment illustrated in FIG. 5, either one or more of BTE audiosensor 544, coil audio sensor 542, cable audio sensor 554, or anycombination thereof may be treated as a single sensor, as describedelsewhere herein. It should also be appreciated by one of ordinary skillin the art that the positions of BTE audio sensor 544, coil audio sensor542, and cable audio sensor 554 nor their respective acousticaltransducers 546, 548 and 556 are not restricted to the positions shownin FIG. 5. It should also be appreciated that various combinations ofacoustical transducers may be implemented in BTE audio sensor 544, coilaudio sensor 542 and/or cable audio sensor 554. As a result, theconfiguration shown in FIG. 5 is merely illustrative. For example, it iswithin the scope of the invention that any sensor could comprise asingle microphone while the other sensors comprises any number ofmicrophones. Furthermore, it is equally within the scope of theinvention for all three of the sensors to comprise a single microphone.In addition, it would also be appreciated by one of ordinary skill inthe art that audio sensors 550 may comprise any combination of BTE audiosensor 544, cable audio sensor 554, and coil audio sensor 542.

As noted above with reference to FIGS. 3 and 4, processor 526 is notlimited to a BTE sound processor and may be any sound processor now orlater developed. For example, processor 526 could be a modularprocessor.

FIG. 6 is a schematic diagram of another embodiment of externalcomponents 122 introduced above with reference to FIG. 1, referred toherein as external components 622. In the embodiment shown in FIG. 6,external components 622 comprise a body-worn sound processor 626implementing an embodiment of an directional sound processor 484(referred to as 684), a headset 664, an embodiment of external coil 130,referred to herein as external coil 630, and a further embodiment ofaudio sensors 250, referred to herein as audio sensors 650. Externalcoil 630 is connected to headset 664 via coil cable 632, while headset664 is connected to processor 626 via headset cable 662.

Body-worn sound processor 626 is a sound processor worn on therecipient's body that contains all the physical elements that arerequired to process sound and generate an appropriate coded stimulationsignal to send to external coil 630. Acoustical transducers of body wornsound processor are usually housed in headset component 664 that isoperationally located behind the recipient's ear. Body-worn soundprocessor 626 acts as the main processing unit.

Audio sensors 650 comprise a plurality of sensors spatially-arranged toreceive ambient sound. Audio sensors 650 may comprise any combination ofa coil audio sensor 642, a cable audio sensor 654, a headset audiosensor 644, a headset cable sensor 674 or a processor sensor 684. Coilaudio sensor 642 is similar to the coil audio sensor described abovewith reference to FIGS. 3-5. Coil audio sensor 642 is disposed onexternal coil 130 and may comprise one or more microphones 648.Similarly, cable audio sensor 654 is similar to the cable audio sensordescribed above with reference to FIG. 5. Cable audio sensor 654 isdisposed on coil cable 632 connecting headset 664 and external coil 630,and may comprise one or more microphones 656.

Headset 664 is similar to a BTE in that it is constructed and arrangedto fit behind the outer ear 112 of a recipient. However, unlike a BTE,headset 664 does not comprise the main processing means for externalcomponents 622.

Headset 664 further comprises a headset sensor 644. Headset sensor 644comprises one or more acoustical transducers, referred to herein asmicrophones 646, disposed in headset 644. Microphones 646 may bedisposed in headset 644 in a variety of positions. The number ofmicrophones 646 in headset sensor 644 may depend on various factorsincluding the particular mechanical design of headset 664, theparticular type of technology used to realize microphones 646, and thedesired characteristics of sensors 650.

Headset cable sensor 674 comprises one or more acoustical transducers638 disposed along headset cable 662. Acoustical transducers 638 may beplaced along the cable with equidistant spacing, or at varying spacing,as noted above. The number of acoustical transducers in headset cablesensor 674 may depend on various factors including but not limited tothose noted elsewhere herein.

Processor audio sensor 684 is disposed on or in body-worn processor 626and may comprise one or more acoustical transducers 658. Acousticaltransducers 658 may be have a variety of configuration and may belocated in a variety of positions. Accordingly, processor audio sensor684 is not limited to the configuration shown in FIG. 6. The number ofacoustical transducers 658 in processor audio sensor 684 may depend onvarious factors including but not limited to those noted elsewhereherein.

As in the other embodiments described herein, microphones 638, 646, 648,656 and 658 may possess a directional or omni-directional polarresponse.

In the illustrated embodiment, ambient sounds are incident on sensors650. Sensors 644, 642, 654, 674 and 684 are spatially-arranged toreceive the ambient sounds with their respective acoustical transducers646, 648, 656, 638 and 658. In certain embodiments, each acousticaltransducer 646, 648, 654, 638 and 658 transmits its received sounds todirectional sound processor 684 in body -worn sound processor 626.Directional sound processor 626 converts the plurality of acousticalsignals from the audio sensors to a single stimulation instructionsignal as described below with reference to FIG. 9.

In alternative embodiments, directional sound processor 684 may treatthe acoustical transducers located in a particular sensor as a singlesensor, as described above with reference to FIG. 4. As noted, in suchan embodiment, the particular audio sensor and/or the component on whichthe sensor is located, further comprises an array-processing stage. Thisarray-processing stage functions substantially similar to thearray-processor discussed below with reference to FIG. 9.

In the embodiment illustrated in FIG. 6, either one or more of headsetaudio sensor 644, coil audio sensor 642, cable audio sensor 654, headsetcable audio sensor 674, processor audio sensor 684, or any combinationsthereof may be treated as a single sensor as described above.

It would be appreciated by one of ordinary skill in the art that thepositions of headset audio sensor 644, coil audio sensor 642, coil cableaudio sensor 654, processor audio sensor 684, and headset cable audiosensor 674 are not restricted to the positions shown in FIG. 6. It wouldalso be appreciated that various combinations of microphones may be usedfor either headset audio sensor 644, coil audio sensor 642, coil cableaudio sensor 654, processor audio sensor 684, and headset cable audiosensor 674. For example, it is envisioned that one or more sensorswithin sensors 650 may comprise a single microphone, while the othersensors comprise a plurality of microphones. Similarly, it is envisionedthat all sensors in sensors 650 may comprise a single microphone.

Furthermore, it would be appreciated by one of ordinary skill in the artthat various combinations may be used to for audio sensors 650. As aresult, the configuration shown in FIG. 6 is merely illustrative. Forexample, it would be appreciated that one or more of headset sensor 644,coil sensor 642, coil cable sensor 654, processor sensor 684, or headsetcable sensor 674 could be omitted from the configuration in variousembodiments.

FIG. 7 is a schematic diagram of the embodiment shown in FIG. 6applicable to bilateral recipients. FIG. 7 illustrates two externalcomponents 722A and 722B. External components 722A and 722B are similarto the external components described above with reference to FIG. 6 inthat each external component 722A and 722B comprises a headset764A/764B, an external coil 730A/730B, and an embodiment of audiosensors 750A/750B. In the embodiment shown in FIG. 7, a body-worn soundprocessor 726 replaces sound processor 626 from FIG. 6. Sound processor726 is connected to headsets 764A, 764B via headset cables 762A, 762B,respectively.

In the embodiment shown in FIG. 7, body-worn sound processor 726comprises one or more sound processors. In one particular embodiment,body-worn sound processor 726 comprises two sound processors. In thisembodiment, each sound processor is connected to one headset 764. Inanother embodiment, body-worn sound processor 726 comprises a singlesound processor connected to both headsets 764 configured to generatestimulation instruction signals for each implant.

In further embodiments, directional sound processor 784 is configured totreat one or more audio sensors on external components 722A and 722B asa single sensor. For example, in such an embodiment, directional soundprocessor 784 is configured to treat a plurality of sounds received fromprocessor cable audio sensors 774A and 774B as a single received soundinput. An advantage of this configuration is that using microphonesignals captured from each side of the head resembles normal hearingmore closely than when using microphone signals captured from one sideof the head. Processor cable sensors 774 may comprise additionalarray-processing stages as described above with reference to FIG. 4. Inother embodiments, directional sound processor 784 may comprise aplurality of array-processing stages as described above.

Despite the type of body-worn sound processor 726 used, externalcomponents 722A and 722B will each comprise audio sensors 750 that aresubstantially similar to audio sensors 650 described above. As such,audio sensors 750 may comprise any combination of a coil audio sensor742, coil cable audio sensor 754, headset audio sensor 744, headsetcable audio sensor 774 or processor audio sensor 784. Coil audio sensor742, coil cable audio sensor 754, headset audio sensor 744 and headsetcable audio sensor 774 each comprise one or more acoustical transducersand are substantially the same as discussed above with reference toFIGS. 3-6.

Processor audio sensors 784 are disposed in body-worn sound processor726 and each comprises one or more acoustical transducers 758.Acoustical transducers 758 may be placed in various positions orconfigurations in body-worn sound processor 726. The number ofacoustical transducers in each processor audio sensor 784 may depend onvarious factors including but not limited to those noted above.

In embodiments of the present invention, microphones 738, 746, 748, 756and 758 may possess a directional or omni-directional polar response.

In the illustrated embodiment, ambient sounds are incident on sensors750. Audio sensors 744, 742, 754, 774 and 784 are spatially-arranged toreceive the ambient sound signals with their respective acousticaltransducers 746, 748, 756, 738 and 758. In certain embodiments, eachacoustical transducer 746, 748, 756, 738 and 758 transmits its receivedsounds to directional sound processor 784 in body-worn speech processor726. Directional sound processor 784 then converts the plurality ofreceived sounds into a single stimulation instruction signal asdescribed below with reference to FIG. 9.

In alternative embodiments, directional sound processor 784 may treatthe acoustical transducers located in a particular audio sensor as asingle sensor, as described above with reference to FIG. 4. As noted, insuch an embodiment, the particular sensor, or the component on which thesensor is located, further comprises an array-processing stage. Thisarray-processing stage functions substantially similar to thearray-processor discussed below with reference to FIG. 9.

In the embodiment illustrated in FIG. 7, either one or more of headsetaudio sensors 744, coil audio sensors 742, cable audio sensors 754,headset cable audio sensors 774, processor audio sensors 784, or anycombinations thereof may be treated as a single audio sensor asdescribed above.

It should further be appreciated by one of ordinary skill in the artthat the positions of headset audio sensors 744, coil audio sensors 742,coil cable audio sensors 754, processor audio sensors 784, and headsetcable audio sensors 774, and their respective acoustical transducers,are not restricted to the positions shown in FIG. 7.

It should further be appreciated that various combinations of acousticaltransducers may be used for either headset audio sensors 744, coil audiosensors 742, coil cable audio sensors 754, processor audio sensors 784,and headset cable audio sensors 774. For example, it is envisioned thatone or more audio sensors within sensors 750 comprises a singlemicrophone or other type acoustical transducer, while the other audiosensors comprise a plurality of microphones or other type of acousticaltransducer. Similarly, it is envisioned that all audio sensors 750 maycomprise a single microphone or other type of acoustical transducer.

Furthermore, it would be appreciated by one of ordinary skill in the artthat various combinations of acoustical transducers may be used to formaudio sensors 750. For example, it would be appreciated that one or moreof headset audio sensors 744, coil audio sensors 742, coil cable audiosensors 754, processor audio sensors 784, or headset cable audio sensors774 could be omitted from the configuration in various embodiments.

FIG. 8 is an illustration of another embodiment of the present inventionapplicable to bilateral recipients. FIG. 8 illustrates two externalcomponents 822A and 822B. In the embodiment shown in FIG. 8, externalcomponents 822A and 822B each comprise an external coil 830 and anembodiment of sensors 250, referred to as audio sensors 850. Eachexternal coil 830 is connected to body-worn sound processor 826 via itsrespective coil cable 896.

External coils 830 are similar to external coils 130 described above; assuch, external coils 830 also comprise a coil audio sensor 842. As withthe other embodiments described herein, external coils 830 may containhardware that partially or fully processes received sounds beforetransferring the sounds to body-worn sound processor 826.

As shown in FIG. 8, body-worn sound processor 826 comprises one or moresound processors. In one particular embodiment, body-worn soundprocessor 826 comprises two sound processors. In this embodiment, eachsound processor is connected to one external coil 830. In anotherembodiment, body-worn sound processor 826 comprises a single soundprocessor connected to both external coils 830 configured to provide astimulation instruction signal to each implant.

Sensors 850 may comprise any combination of a coil sensor 842, a coilcable sensor 886 or a processor sensor 884. Coil sensor 842 is similarto the coil sensor discussed above with reference to FIGS. 3-7.Similarly, coil cable sensor 886 is similar to the coil cable sensorsdiscussed above with reference to FIGS. 5-7. Each coil cable sensor 886is disposed on coil cable 896 connecting external coil 830 and body-wornsound processor 826, and may comprise one or more microphones 888.Microphones 888 are disposed along coil cable 896 with equidistantspacing, or at varying spacing.

Processor sensors 884 are disposed in body-worn sound processor 826 andmay comprise one or more microphones 858. Microphones 858 may be inbody-worn sound processor 826 in a variety of positions andconfigurations and is not limited to the configurations shown in FIG. 8.The number of microphones 858 in processor sensors 884 may depend onvarious factors including the particular mechanical design of body-wornsound processor 826, the particular type of technology used to realizemicrophones 858, and the desired characteristics of sensors 850.

In embodiments of the present invention, microphones 848, 858 and 888may possess a directional or omni-directional polar response.

In the illustrated embodiment, ambient sounds are incident on sensors850. Sensors 842, 884 and 886 are spatially-arranged to receive theambient sounds with their respective microphones 848, 858 and 888. Incertain embodiments, each microphone 848, 858 and 888 transmits itsreceived sounds to directional sound processor 884 in body-worn speechprocessor 826. Directional sound processor 884 then converts theplurality of received sounds into a single stimulation instructionsignal as described below with reference to FIG. 9.

In alternative embodiments, directional sound processor 884 may treatthe microphones located in a particular sensor as a single sensor, asdescribed above with reference to FIG. 4. As noted, in such anembodiment, the particular sensor, or the component on which the sensoris located, further comprises an array-processing stage. Thisarray-processing stage functions substantially similar to thearray-processing stages discussed below with reference to FIG. 9.

In the embodiment illustrated in FIG. 8, either one or more of coilsensors 842, coil cable sensors 886 or processor sensors 884, or anycombinations thereof may be treated as a single sensor as describedabove.

It would be appreciated by one of ordinary skill in the art that thepositions of coil sensors 842, coil cable sensors 886, processor sensors884 are not restricted to the positions shown in FIG. 8. It would alsobe appreciated that various combinations of microphones may be used foreither coil sensors 842, coil cable sensors 886, processor sensors 884.For example, it is envisioned that one or more sensors within sensors850 could comprise a single microphone, while the other sensors comprisea plurality of microphones. Similarly, it is envisioned that all sensorsin sensors 850 could comprise a single microphone.

Furthermore, it would be appreciated by one of ordinary skill in the artthat various combinations may be used to make up sensors 850. As aresult, the configuration shown in FIG. 8 is merely illustrative. Forexample, it would be appreciated that one or more of coil sensors 842,coil cable sensors 886, processor sensors 884 could be omitted from theconfiguration in various embodiments.

It would also be appreciated that the above described embodiment isequally applicable to a recipient with a single implant. In such anembodiment, only one set of external components 822 would be used. Insuch an embodiment, body-worn sound processor 826 would comprise asingle sound processor 884.

It should be appreciated by one of ordinary skill in the art that theacoustical transducers utilized in the embodiments described herein withreference to FIGS. 3-8 may be any acoustical transducers now or laterdeveloped that receives as an input an acoustic signal and that convertsthat signal to an electrical form, either analog or digital, for furtherprocessing. The acoustical transducers of the present invention are notlimited to any particular type of technology known or later developed.For example, the acoustical transducers may be realized using electretcondenser technology or MEMS (Micro-Electro-Mechanical-Systems)technology.

Furthermore, in the embodiments described above with reference to FIGS.3-8, the transmission of sounds and signals may be accomplished throughwireless transmission as well as through cables connecting variouscomponents. Although the various embodiments have been illustrated withcables connecting the various components, embodiments that do notrequire cables are equally within the scope of the invention.

Embodiments of directional sound processor 284 are described next belowwith reference to FIG. 9. As noted, in each exemplary embodiment ofaudio sensors 250 described above with reference to FIGS. 3 through 8,the embodiment of directional sound processor 284 implemented in suchembodiments, was referenced by a unique reference number 384, 484, 584,684, 784 and 884, respectively. The embodiments of directional soundprocessor 284 described next below may be implemented as any one of suchembodiments.

As shown in FIG. 2, directional sound processor 284 comprises an arrayprocessor 280 and a conventional sound processor 282. As noted,array-processing, also commonly referred to as beamforming, refers tothe field of sound processing utilizing an array of audio sensors thatare spatially-arranged to receive ambient sounds. Array-processingcreates a beam pattern, that is more directive or sensitive to soundspropagating from a desired direction, compared to the directivity orsensitivity of an individual sensor receiver alone. In other words,array processing increases the signal-to-noise ratio (SNR) for soundssensed from a desired direction while sounds sensed from otherdirections will be attenuated. The desired direction can be at a fixedangle or determined based on, for example, the amplitudes of theincident ambient sounds.

FIG. 9 illustrates a beam pattern created by the array-processing of thepresent invention. The term beam pattern refers to how the sensitivityof a set of audio sensors vary in three dimensions to sounds propagatingtoward the sensors from any direction. The beam pattern indicates howwell a sound signal from a given direction will be attenuated relativeto the maximum sensitivity of the array. A null in the beam pattern is alocation where the sensitivity of the array has been significantlyreduced, indicating that a sound signal propagating toward the arrayfrom that direction will be attenuated relative to sounds propagatingtoward the array from the desired direction. Nulls are desirablecharacteristics, and in array-processing algorithms it is possible tosteer nulls toward specific directions and thereby attenuate interferingsignals by using delay and sum techniques or adaptive noise cancellationtechniques for example.

In FIG. 9, a sound is received at two microphones in accordance with theembodiment of the present invention illustrated in FIG. 3. The beampattern shown in FIG. 9 is taken along a single horizontal plane. Thearray-processing of this embodiment creates a null along axis 920 whichis at 180 degrees from the direction of maximum sensitivity. The systemhas maximum sensitivity to sounds propagating towards the array alongaxis 920 from the zero-degree direction. The array-processor interpretssuch sounds as desired sounds, while sounds received from otherdirections are interpreted as noise signals. The array-processingalgorithms mathematically combine sounds propagating along or near axis920 from the zero degree direction into the directional sound signalwhile eliminating the noise signals. It should also be noted that thearray processing algorithms are not limited to directions of maximumsensitivity.

Several types of array-processing algorithms may be used to convert aplurality of sounds received by the audio sensors into a directionalsound signal. For example, in one embodiment, the array-processingalgorithm that is used is of the type as described inBlind Beamformingon a Randomly Distributed Sensors System, Kung Yao et. al., 1998 IEEEJournal on Selected Areas in Communications, Vol. 16, No 8, which ishereby incorporated by reference herein. Such an algorithm as describedin this reference may be usefully applied to enable a randomdistribution of sensors and microphones to be used. With a randomdistribution of sensors and microphones, the location of each cannot beknown exactly due to anatomical differences between recipients. However,the use of adaptive algorithms and source localization algorithms suchas blind beamforming can overcome this issue.

In such an embodiment, it is not necessary for the array-processingalgorithms to be provided with the exact location of each acousticaltransducer or sensor. From the group of individual input signals fromeach acoustical transducer, directional sound processor 284 calculatesan ensemble averaged correlation matrix of the received sensor datavector to determine the source of the highest peak power spectraldensity. The array weights are obtained from the dominant eigenvector ofa matrix eigenvalue problem.

In an alternative embodiment, an array-processing algorithm may beimplemented which relies upon known spatial dimensions between each oneof the sensors or acoustical transducers. This type of array-processingalgorithm may be of the type described in U.S. Pat. No. 6,888,949, whichis hereby incorporated by reference herein. Similarly, thearray-processing algorithm of this embodiment could be of the typedescribed in WO 2005/006808, which is hereby incorporated by referenceherein.

Further embodiments of array-processor 280 may use noise cancelingadaptive filtering within the array-processing algorithm. In such anembodiment, the adaptive algorithm would use a noise reference signal aspart of the processing scheme. A particular sensor is chosen as thesensor to receive a noise reference signal. In one particularembodiment, the coil sensor is chosen as the sensor that provides thenoise reference signal. The coil sensor is chosen because the physicallocation of the transmitter coil on the recipient's head lends itself toproviding a better noise reference to the array-processing algorithms,given its proximity to noise signals propagating from the rear of therecipient. The difference in amplitudes of the noise signals received bythe coil sensor and other microphones will be more pronounced, makingthe signal from the coil sensor better suited to be a noise reference,given that the desired signal the recipient wishes to hear typicallypropagates toward the sensors from the front of the recipient.

As noted, FIG. 9 illustrates the beam pattern resulting from the use oftwo microphones, similar to the embodiment illustrated in FIG. 3. Theuse of additional sensors and microphones, as described with referenceto FIGS. 4-8 extends the array of sensors, thereby increasing the arrayaperture and making the beam pattern more directional. The larger theaperture of the sensors, the better the resolution of the sensors, andhence the greater the flexibility to tailor the beam pattern. Resolutioncorresponds to the width of the main beam in the beam pattern. Adecrease in the width of the main beam results in increased directivityin the desired direction and greater noise reduction in the otherdirections. Furthermore, there is no need for the sensors to bepositioned in a symmetrical pattern.

In still further embodiments, the varying of the spacing between themicrophones in a sensor results in tailoring of the array-processingalgorithms to receive signals of particular frequencies more optimally.Recall that low frequency signals have large wavelengths. This means themicrophone elements should be placed further apart than for highfrequency signals in order to better discriminate the low frequencysignal.

Throughout this specification the word “comprise”, or variations such as“comprises” or “comprising”, will be understood to imply the inclusionof a stated element, integer or step, or group of elements, integers orsteps, but not the exclusion of any other element, integer or step, orgroup of elements, integers or steps.

It will be appreciated by persons skilled in the art that numerousvariations and/or modifications may be made to the invention as shown inthe specific embodiments without departing from the spirit or scope ofthe invention as broadly described. The present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive.

Any discussion of documents, acts, materials, devices, articles or thelike which has been included in the present specification is solely forthe purpose of providing a context for the present invention. It is notto be taken as an admission that any of these matters form part of theprior art or were common general knowledge in the field relevant to thepresent invention as it existed before the priority date of each claimof this application.

What is claimed is:
 1. A cochlear implant comprising: a behind the ear(BTE) sound processing unit; a cable; a transmit unit connected to saidBTE by said cable and configured to transmit signals from said BTE to aninternal component of said cochlear implant; a plurality ofspatially-arranged audio sensors, configured to receive ambient sound,and comprising any combination of: a sensor located in said BTE, asensor located in said transmit unit, and a sensor located in saidcable; and a directional sound processor having an array-processingstage configured to generate a directional sound signal from soundreceived by a first one of said plurality of sensors, and wherein saiddirectional sound processor is configured to utilize combine saiddirectional sound signal and a signal representative of sound receivedby a second one of said plurality of sensors to generate a processedsound signal from which sound received from non-desired directions isattenuated.
 2. The cochlear implant system of claim 1, wherein each ofthe BTE, the cable and the transmit unit are comprised in a singlecochlear implant.
 3. The cochlear implant system of 1, wherein thecochlear implant system comprises a single cochlear implant.
 4. Thecochlear implant of claim 1, wherein each of said plurality of sensorscomprises at least one acoustical transducer.
 5. The cochlear implant ofclaim 1, wherein one or more of said plurality of sensors each comprisea plurality of acoustical transducers.
 6. The cochlear implant of claim1, further comprising: a directional sound processor configured toprocess sound received by said audio sensors from one or more desireddirections, and to attenuate sound received from directions other thansaid desired directions.
 7. The cochlear implant of claim 1, whereinsaid directional sound signal is an enhanced representation of saidsound received by said first one of said sensors from one or moredesired directions.
 8. The cochlear implant of claim 7, wherein said oneor more desired directions are determined based on the amplitudes of theincident ambient sounds.
 9. The cochlear implant of claim 1, whereinsaid processed sound signal is a stimulation instruction signal.
 10. Thecochlear implant of claim 1, wherein said first one of said plurality ofsensors comprises: one or more acoustical transducers, and wherein saidarray-processing stage is configured to generate said directional soundsignal from sound received by said one or more acoustical transducers.11. The cochlear implant of claim 10, wherein said directional soundprocessor further comprises: at least a second array-processing stageconfigured to generate a second directional sound signal from said soundreceived by said second one of said plurality of sensors-as said signalrepresentative of sound received by a second one of said plurality ofsensors.